Anaerobic Respiration in Plants

In the plant world, anaerobic respiration, or respiration without using oxygen, is known as fermentation. This process is commonly used to our advantage in the production of beer and ales where barley, hops and other grains are fermented to produce alcohol, a natural by-product of anaerobic respiration in plants.

Respiration in plants begins with photosynthesis. Plant cells contain organelles known as chloroplasts. Inside the chloroplasts is the substance called chlorophyll, which is what gives plants their green color. Plants absorb water through the root system and take in carbon dioxide through tiny openings in the leaves called stomata. Using the sun’s energy and the chlorophyll, the plant converts the water and carbon dioxide into glucose and starches. The by-product of this is oxygen, most of which is released back into the air.

Respiration in plants is a chemical process that breaks down glucose provided by photosynthesis to provide energy for the plant’s cells. Under most conditions this respiration is aerobic and has two forms, photorespiration and dark respiration. Photorespiration occurs in daylight and happens at the same time as photosynthesis. Dark respiration happens at night and requires that the plant take in oxygen and release carbon dioxide, which is the reverse of what happens during the day.

When no oxygen is present, plants can temporarily use anaerobic respiration to create energy. It is not as efficient, since the glucose molecule does not break down completely, but rather changes into ethyl alcohol and carbon dioxide and creates only two molecules of ATP, or adenosine triphosphate. ATP is a means of storing energy in the form of sugars at the cellular level. Plants cannot keep up the anaerobic respiration process for long, only a few days at most. The parts of the plants that were using this type of respiration eventually die. There are exceptions, such as germinating seeds planted underground and certain species of fungi.